package qinyi365;

import java.io.ByteArrayOutputStream;

public class Base64 {
	private static char[] base64EncodeChars = new char[] {    
	       'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',    
	       'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',    
	       'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',    
	       'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',    
	       'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',    
	       'o', 'p', 'q', 'r', 's', 't', 'u', 'v',    
	       'w', 'x', 'y', 'z', '0', '1', '2', '3',    
	       '4', '5', '6', '7', '8', '9', '+', '/' };    
	    
	   private static byte[] base64DecodeChars = new byte[] {    
	   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,    
	   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,    
	   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,    
	   52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,    
	   -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,    
	   15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,    
	   -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,    
	   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };    
	    
	   Base64() {}    
	    
	   public static String encode(byte[] data) {    
	       StringBuffer sb = new StringBuffer();    
	       int len = data.length;    
	       int i = 0;    
	       int b1, b2, b3;    
	    
	       while (i < len) {    
	           b1 = data[i++] & 0xff;    
	           if (i == len) {    
	               sb.append(base64EncodeChars[b1 >>> 2]);    
	               sb.append(base64EncodeChars[(b1 & 0x3) << 4]);    
	               sb.append("==");    
	               break;    
	           }    
	           b2 = data[i++] & 0xff;    
	           if (i == len) {    
	               sb.append(base64EncodeChars[b1 >>> 2]);    
	               sb.append(    
	                       base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);    
	               sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);    
	               sb.append("=");    
	               break;    
	           }    
	           b3 = data[i++] & 0xff;    
	           sb.append(base64EncodeChars[b1 >>> 2]);    
	           sb.append(    
	                   base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);    
	           sb.append(    
	                   base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);    
	           sb.append(base64EncodeChars[b3 & 0x3f]);    
	       }    
	       return sb.toString();    
	   }    
	    
	   public static byte[] decode(String str) {    
	       byte[] data = str.getBytes();    
	       int len = data.length;    
	       ByteArrayOutputStream buf = new ByteArrayOutputStream(len);    
	       int i = 0;    
	       int b1, b2, b3, b4;    
	    
	       while (i < len) {    
	    
	               
	           do {    
	               b1 = base64DecodeChars[data[i++]];    
	           } while (i < len && b1 == -1);    
	           if (b1 == -1) {    
	               break;    
	           }    
	    
	               
	           do {    
	               b2 = base64DecodeChars[data[i++]];    
	           } while (i < len && b2 == -1);    
	           if (b2 == -1) {    
	               break;    
	           }    
	           buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));    
	    
	               
	           do {    
	               b3 = data[i++];    
	               if (b3 == 61) {    
	                   return buf.toByteArray();    
	               }    
	               b3 = base64DecodeChars[b3];    
	           } while (i < len && b3 == -1);    
	           if (b3 == -1) {    
	               break;    
	           }    
	           buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));    
	    
	               
	           do {    
	               b4 = data[i++];    
	               if (b4 == 61) {    
	                   return buf.toByteArray();    
	               }    
	               b4 = base64DecodeChars[b4];    
	           } while (i < len && b4 == -1);    
	           if (b4 == -1) {    
	               break;    
	           }    
	           buf.write((int) (((b3 & 0x03) << 6) | b4));    
	       }    
	       return buf.toByteArray();    
	   }    
}
